How to model/apply a rhomboid pattern on a cylinder? (Sword hilt modeling)
Subdivide your cylinder vertically the number of desired times with a Loopcut.

Select all faces and use the Poke operator to turn them into rhombus.

Using the Select Similar operator (Shift+G by default) select all horizontal edges and erase them with the Dissolve option, making sure you keep the ones defining the cylinder top and bottom edges.

Repeat the process for the vertical edges by Select Similar then Dissolve.
Done!